Automatic director telephone system



May 22, 1951 a. MOLNAR AUTOMATIC DIRECTOR TELEPHONE SYSTEM Fi led Dec.8. 1947 9 Sheets-Sheet 1 3 ill. T 'H g m n 7 V Q m l fi v A I. [s 4 h 17 M N m Tm; m mh Q gall. 1 ENE mohumE IMRE MOLNAR ,M. Z I ATTORNEY May22, 1951 a. MOLNAR AUTOMATIC DIRECTOR TELEPHONE SYSTEM 9 Sheets-Sheet 2Filed Dec. 8. 1947 @imum! Human E m2 @186 m t 2; 3. 68 mm mm t. E Q 55 W8m 3 w m m rte m3. 8. 2 m 526 $2 3. 2 m Eto as we :2 E. at at 22K m n. au 9.

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9 Sheets-Sheet 5 l. MOLNAR INVENTO; IMRE MOLNAR .BY 5 r7 ATTORNEYAUTOMATIC DIRECTOR TELEPHONE SYSTEM May 22, 1951 Filed Dec. 8, 1947 May22, 1951 1. MOLNAR AUTOMATIC DIRECTOR TELEPHONE SYSTEM 9 Sheets-Sheet 6Filed Dec. 8, 1947 mmum 2:1 mnou uQEuO wmmm INVENTOR.

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ATTO RNEY May 22, 1951 l. MOLNAR AUTOMATIC DI RE 2CTOR TELEPHONE SYSTEM9 Sheets-Sheet 7 Filed Dec. a, 1947 I OD x IN VEN TOR. IMRE MOLN ARATTOR NEY May 22, 1951 MOLNAR AUTOMATIC DIRECTOR TELEPHONE SYSTEM 9Sheets-Sheet 8 Filed Dec. 8. 1947 I INVENTOR. IMRE MOLNAR n 5m hmmn r 8mE m QE ATTORNEY R A N L 0 M AUTOMATIC DIRECTOR TELEPHONE SYSTEM FiledDec. 8,' 1947 7 9 Sheets-Sheet 9 MULT. TO OTHER DSR RLYS.

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mm: MOLNAR ATTO rmsv Patented May 22, 1951 UNITED STATES PATENT OFFICEAUTOMATIC DIRECTOR TELEPHONE SYSTEM Imre Molnar, Chicago, Ill., assignorto Automatic Electric Laboratories,lnc., Chicago, 111., a corporation ofDelaware 23 Claims. 1

The present invention relates to telephone systems, and particularly tomulti-ofiice universal numbering systems of the step-by-step type inwhich translating register-senders, commonly known as directors areemployed for routing calls. Such register senders are particularlyuseful in large networks to eliminate the need for trunking from eachoifice to every other office and promote greater trunk efficiency, byregistering the digits of a call number and retransmitting the same ordifferent digits in greater or lesser number to route the call to thedesired ofiice by the quickest route in accordance with the location ofthe originating oiiice.

The main object of my invention is the provision of a simple and lowcost director arrangement for use in small networks in which the variousoflices are too far apart for direct connections, but must be trunkedtogether in tandem. One application for such a director arrangement isfor a private system for an oil or mining concern, in which fastcommunication is desired between a number of scattered privateexchanges.

One feature of the invention is accordingly the use of an all relaydirector-selector which, instead of being individual to the selectors,is common to all of the selectors and directors in the office.

Another feature of the invention is the use of a coding office registerresponsive to only a single office selecting digit for setting up thedifferent outgoing office codes.

A further feature of the invention is the reuse of the ofiice registeras a line digit register. This is done by operating a small group ofcoding relays in various combinations from the of'ice register, lockingup the operated relays and then releasing the register, which isprovided with two banks for the double use.

Still another feature of the invention is the inclusion of a restrictingrelay with the coding relays and then operating said relay from certaincalling lines, or from certain positions of said oiiice registercorresponding to an unused office digit, for cancelling an existing codeset-up and substituting a different code for directing the call to aspecial number.

Another feature is the use of a relay interrupter individual to eachdirector for generating the outgoing pulses.

Other objects and features of the invention will be apparent from thespecification and claims which follow, when considered in conjunctionwith the accompanying drawings com prising Figures 1 to 11 inclusive.

Figure 1 shows a small telephone network comprising telephone exchangesC, Q, J, P, A, and S.

Figures 2 and 3 diagrammatically illustrate the trunking arrangement andthe necessary apparatus for this telephone network.

Figures 4 to 10, inclusive, show some of the apparatus at exchange J indetail circuit diagrams.

Figure 4 for example illustrates the subscribers lines C and C, therotary line switches RLS, the first selector FS, the incoming selector13!, and the connector CS, in diagrammatic form, and the second selectorSS in a detail circuit digram.

Figure 5 diagrammatically illustrates an allrelay director-finder DF forinterconnecting the second selectors, such as SS, with idle ones of thedirectors, DR.

Figures 6, '7, 8 and 9 show the circuit details of one of the directorsat exchange J.

Figure 10 shows the circuit details of the director test set at exchangeJ.

Figure 11 (included with Figure 3) shows the digits transmitted by thedirector in response to the second digit of the office code oninteroffice calls. Since there is no director at exchange P there is notranslation, and both oifice digits are shown as dialled.

Referring to Figures 1, 2 and 3, a general description of the trunkingarrangement will now be given. Calls originating at exchange 0 extendthrough individual lines switches of the Well-known rotary step-by-steptype andautomatically select idle first selectors of the wellknownStrowger vertical and rotary type. Local calls within the exchange 0 canbe made by directly dialling the local subscribers number, or bydialling the office code 7 9 of exchange C and then the subscribersnumber. Local subscriber numbers are in the two, three, four and fivehundred groups and therefore when "the first local subscribers digit isdialled, said 3 for example, the first selector is operated to the thirdlevel and automatically selects a connector in the three-hundred group.No director is needed in this connection and then in response to thedialled tens and units digits, the seized conhector, which is also ofthe well-known Strowger vertical and rotary type, is operatedstep-by-step to connect with the local called subscribers line. In casethe calling subscriber prefixes the ofiice code 79 to the subscribersnumber then the first selector is operated to the seventh level inresponse to the first digit 7 to seize an idle director and secondselector. In response to the next digit 9 and the subscribers digits,the director is operated to record these digits. In this case, since thecall is a local call, the director skips the office code digits andtransmits only the subscribers number without translation to operate thesecond selector to the second, third, fourth or fifth level, dependenton the called subscribers hundreds digit, to seize an idle connector inthe corresponding hundreds group: The seized connector is operated bythe. tens and units digits transmitted from the director to connect withthe called line.

In case a subscriber at exchange C desires to call a subscriber atexchange Q the calling subscriber dials the office code 78 of exchange Qand then the subscribers number; lector at exchange C is operated to theseventh level to seize an idle director and second selector in responseto the first digit 7. In response to the second: digit 8 and thesubscribers digits the seized director records. such digits and thenretransmits. the digit 8 to operateathe second selector to the eighthlevel'to seize an idle repeater R'I. terminating one of the trunksextending to exchange Q. The director then transmits the subscribersnumber causing: operation of repeaters RI and R2 and an incomingselector and a. connector at exchange Q to complete the call to thecalled subscriber.

Callsfrom exchangeC to exchange J are taken care of in a similar mannerby dialling the office code.77 and thesubscribers digits, but in thiscase thesecond digit '7'! dialled into the director'istranslatedftotransmit the digit 1 thereby operatingthe second selectorto its firstlevel. to route the call over one of the trunks and theassociatedrepeaters, such as repeaters R3 and R4, after which theincoming selector ISl and connector CS; areoperated by the subscriberdigits to complete the desired connection to a called; line in; exchangeJ.

Calls from exchange C to exchanges beyond Jtarevextended throughexchange J. In calls to exchange P the' ofiice code 81 is dialled andtherr the subscribersdigits. The director seized from the eighth level:of: the first selector in exchange 'C responds to the seconddigit 1 andtranslates this digit into the digits 1 and "6 to operate the secondselectorin exchange C to therfi'rst level to connect with atrunk toexchange Jwand to then operate the'incoming selector IS! in exchange Jto the'sixth level to seize a trunk, including repeaters such as R7 andR8, to exchange-P wherean incoming selector and a connecter are:operated by the subscriber digits to connect to thecalled line, such asline D.

In calls from exchange C to exchange A, the office code-66- and thesubscribers digits are dialled by the calling subscriber. The directorseized from the sixth level of the first selector in exchange C receivesthesecond digit 6 and the subscribersdigits and translates the seconddigit 6intothe digits 1,6 and 6 to route the callsaspreviouslydescribedto exchange P where an incomingsselector is operated to the sixth levelto selecta .trunkincluding repeaters such as repeaters" R3 and Rliiextending to exchange A. In: response. to the subscriber digitsretransmitted from the director at exchange C, an incoming'selectoranda: connector at exchange A are operatedto complete. the call to thecalled linesuch as line Incalls from exchange. C to exchange S theofiice. code 65. and the subscribers digits'are The first se dialled bythe calling subscriber. The director seized from the sixth level of thefirst selector in exchange C receives the second digit 5 and thesubscribers digits and translates the second digit 5 into digits 1, 6, 6and 5 to route the call to exchange A, as previously described, wherethe incoming selector is operated to the fifth level to select a' trunk,including repeaters such as RI 1 and BIZ, extending to exchange S. Theretransmitted subscriber digits then operate an incoming selector and aconnector at exchange 8- to complete the call to the called line such asline F.

Local calls in exchanges Q, J, A and S are made inthe same manner asexplained for exchange C, by either dialling only thesubscribers digits,or by dialling the-local ofiice code plus the subscribers digits. In thefirst case the directors are by-passed, and in the second case theyabsorbthe office code digits and retransmit only the subscribers digits.Inter-exchange calls from exchanges Q,'J, A. and S are also made in thesame manner as explained for exchange C, the first selectors-thereatbeing operated in accordance-with the'first digit of the received oilicecode, Whilethe directors translate the second digit of the officecoderinto the digit or digits required to route the call to the wantedexchange. The twodigit ofiicecodes for exchanges'C, Q, J, P, A and S arerespectively 79, 78, 77, 81, 66 and 65, thesecond digits ofwhich aretranslated into one, two, three or four digits as necessary, asindicated in Figure 11.

In? calls from. exchange Q to exchange C, the ofiice code 79 is dialled,and the director seized from the 7th level ofthe first selector atexchange Q,v retransmits the second digit "9 to cause the secondselectorat exchange Q to select an idle trunkto exchange C. over the 9thlevel. In calls from exchange Q to exchange J the director seized. fromthe. 7th level translates the second digit 7 to the digit "1. In callsfrom exchange Q to exchangeP the director seized from the 8th level ofthe first selector translates the second digit 1 to the digits "1 6. Incalls from exchange Q to exchange A the director seized from the 6thlevel of the first selector translates the second digit 6 of the ofiicecode to the digits 166, and in calls to exchange S. this directortranslates the second ofiice digit to digits 1665.

In calls from exchange J to exchanges Q and C the office selectingdigits transmitted by the director at J are 8 and 9 respectively. Incalls from exchange J to exchange P the ofiice selecting digit is digit6, to exchange A the digits are 6 and 6, and to exchange S the digitsare ((6,!) ((6 (5') In calls from exchange A to exchange S the ofiiceselecting digit 5 is transmitted from the director to operate the secondselector at exchange A to the fifth level to select a trunk to exchangeS. In calls from exchange A to P, J, Q and C'the oifice selecting digitstransmitted from the director at exchange A are respectively 1, ((17,);(178;) ((179.3)

In calls from exchange S to exchanges A, P, J, Q and C the respectiveoflice selecting digits transmittedfrcm the director exchange S are 1,"11, 117, 1178 and 1179.

It will be noted that exchange P does not have a director, since anyexchange in the network can be reached from exchange P by means of theregular two-digit ofilce code, without translation. In a larger networkthis might not be possible, in; which case directors would be providedat all exchanges. In the present instance in the case of a call fromexchange P to exchange S the calling subscriber first dials the ofiicecode 65 of exchange S and then the subscribers number, in the usualmanner. In response to the first digit 6, the first selector at exchangeP engages a trunk including repeaters such as R9 and RH extending toexchange A. In response to the second digit 5 the right hand incomingselector in exchange A is operated to the fifth level to extend the callto the incoming selector in exchange S through repeaters such as RH andRi An incoming selector and a connector in exchange S are then operatedby the subscriber digits to complete the connection to a called line inexchange S.

In a call from exchange P to exchange A the ofiice code "66 is dialled.The first selector at exchange P is again operated to the sixth level toseize a trunk to exchange A and to seize the right-hand incomingselector thereat. sponse to the second digit 6, this incoming selectoris operated to the sixth level from which it automatically restores tonormal. selectors of this type are well-known and are similar to thatshown in Lomax Patent 1,747, l78 issued February 18, 1930. In responseto the remaining digits, this incoming selector and a connector areoperated to complete the call in the usual way. i

In calls from exchange P'to exchange J, the office code 7'7 is dialledand the first selector at exchange P is operated to the seventh level toseize the incoming selector 1S3 in exchange J over a trunk includingrepeaters such as R8 and RI. The incoming selector 183 is also of thedrop-back type and is arranged to release whenever the seventh level isdialled. Therefore, in response to the second dialled digit 7 theincoming selector 1S3 drops back to normal and is then re operated bythe first dialled subscribers digit to select an idle connector which isthen operated to complete the call. Calls from exchange P to the otherexchanges are made in the well-known manner and need not be described.The repeaters diagrammatically shown in Figures 2 and 3 are of thewell-known two-way automatic-to-automatic telephone type for repeatingpulses in either direction over the two conductor trunks intercomnecting the exchanges.

In Figure 4 two of the subscribers lines terminating in exchange J areshown at C and C. The subscribers lines in the exchanges have individualrotary line switches, such as RLS, associated therewith. Rotary lineswitches of this type are well-known and are used to automaticallyselect an idle one of the first selectors such as FS, in response to theinitiation of a call at this exchange. The first selectors are of thewellknown Strowger vertical and rotary type and as" shown have access tosecond selectors, such as SS, on certain levels and to local connectorswitches, such as CS, on other levels. The local connector switches arealso of the' well-known Strowger vertical and rotary type and haveaccess to the subscribers lines, such as C and C, terminating inexchange J. The second selector SS is also a Strowger switch and hasaccess through its bank contact levels to the local connectors, and torepeaters terminating trunks to adjacent exchanges C, Q, and P asillustrated in Figure 2.

Figure 5 diagrammatically illustrates an allrelay director-finder DF foroperatively connecting second selectors, such as SS, to an idledirector, such as DR, shown in Figures 6, '7, 8 and 9.

In re- Drop back as relay 556.

6 A start relay 530 is individual to the selector SS and each other suchselector has a corresponding individual start relay, such as relays 5M]and 550. These individual selector start relays are arranged in a chaincircuit with a common relay 529 so that only one of said start relayscan be operated at a time. Connect relays, such as relay Elli, 5H? and5H!" and provided to interconnect the second selectors to idledirectors. There is one connect relay, such as relay 5"), per selectorper director, i. e., the relay am is provided to connect the secondselector SS to the director shown in Figures 6, 7, 8 and 9, anotherconnect relay (not shown) is provided to connect selector 5 SS to thesecond director and so on. The connect relays 5H! for connecting theselector SS to the associated directors have their operating circuitconnected in multiple as indicated through the common resistance R tonegative battery. In a similar manner the connect relays 516, which areassociated with the second of the second selectors are multipled throughthe common resistance R to negative battery. Each selector, thereforehas as many connect relays, such as relay m, as there are directors forassociation with said selector.

In the upper right-hand corner is a chain of relays 556, 56?, 563 and569, one relay per director, ior allotting idle directors for use inrotation. The circuit for relay 5% is shown in full while the remainingrelay circuits are only diagrammatically illustrated, it beingunderstood that each relay 561, 568 and 569 is connected to itscorresponding director in the same marmer Relays 538 and 596 arearranged to operate after the last idle director has been taken into useto reset and re-operate all allotter relays 556, 561, 568 and 569corresponding to directors which are idle at that time. These relays arethen held energized until the associated director is taken into use. Therelay 516 is an all-director-busy relay which is normally energized aslong as any one of the directors is idle.

A portion of the director DR is shown in Figure 6. The relays H6, 63B,69B and 666 in this figure are input control relays one of which isoperated after each incoming dialled digit to transfer the impulses ofthe respective incoming digits to the proper minor switch registeringdevices in Figure 8. It should be noted however that these relays aredifferential relays of the type which operate their contacts in responseto an inductive surge when their circuits are opened.

The relays let! to Hi} shown in Figure '7, are coding relays controlledby the second digit of the office or exchange code for controlling thecircuits which route the call through to the proper exchange. In theupper left hand corner of Figure 7 is shown a cross-connectingarrangement for connecting up service restrictions in accordance withthe class of the connected calling line, which may have unlimitedservice, partially restricted service, or fully restricted service,dependent upon the absence of potential, limited potential or fullpotential connected to the subscribers extra control terminal is shownat the lineswitch RLS in Figure 4. Another cross connecting arrangementis shown in the upper portion of Figure 7 for cross connecting thecontacts of the office code relays to the ten conductors of cable 66!]which are multipled to the bank contacts of the minor switches in Figure8 and to the contacts of the counting relays in Figure 9, forcontrolling the transmission of the proper impulse codes, to route .thecalls to their corresponding destination. In this arrangement the firstdigit dialled into the director causes the operation of an exchange, orofiice, code relay which closes a group of circuits which can be crossconnected through the jumpering field for translating the single digitinto any digit or digits up to five digits.

In Figure 8 are shown the director registering devices U, T and H whichregister the incoming dialled digits, and a sequence control switch SCfor controlling the sequence of outgoing digits. The registering devicesU, T and .H and switch SC are commonly known as minor switches having amagnet for rotating the wipers one step for each impulse received and arelease magnet for restoring such wipers to normal. The minor switch Ufirst operated in response to the receipt of the incoming second digitof the ofiice code to control the operation of the officc code relays inFigure '7 after which it is released and then later reoperated inaccordance with the receipt of the units digit of the called line. minorswitches H and T are set in accordance with the hundreds and tens digitsof the called line.

Relays 950, 953 and 955 in Figure 9 are interrupter relays forgenerating the director's outgoing impulses. Relays 960, 963, 966, N2,916, 986, 99l and 9M are a group of counting relays which are operatedto count the impulses in each outgoing digit. Relay 94%) is a relaywhich is operated on certain calls for a purpose to be explained morefully hereafter. Relays sec and 939 are differential stop relays whichare controlled thru contacts of the counting relays to stop furthertransmission of outgoing pulses at the proper time.

The director routine test circuit in Figure 10 comprises a hand operatedswitch HS having 2 wipers WI and W2 for selecting the director to betested. A milliammeter MA, an impulse dial CD, a minor switch LS forlighting a such as lamp LPI, to indicate the digit dialled ortransmitted by the director, and a number of keys and relays. There isone DSR relay 19H) for each director and the leads, such as conductorsDI and El, terminate in the banks of the switch HS. The test circuitsare multipled, as indicated, to contacts on all the director switchingrelays DSR so that each director can be tested.

Having given a general description of the invention, detail descriptionswill now be given of the circuit operations of the apparatus inextending calls to local and distant subscriber lines. For example,since only part of the equipment in the exchange network is shown indetail in the exchange J, the detail descriptions will be given of callsoriginating from exchange J, it being understood that calls originatingfrom other exchanges use similar apparatus which function in a similarmanner.

Local calls It will now be assumed that the subscriber C in exchange Jdesires to complete a local call to subscriber C whose line alsoterminates in the same exchange. The trunking arrangement is such thatin making a local call the calling subsoriber may either dial the lastthree digits of the called local subscribers number or may dial theofiice, or exchange, code digits before dialling the last three digitsof the local called subscribers number. Let it be assumed first that thecalling subscriber omits dialling the ofiice code digits and thereforedials only the last three digits of the called local number, which wewill assume are the digits 4, 5 and 6.

In response to subscriber C removing his receiver, a circuit iscompleted over his line conductors i0 and II for operating the linerelay (not shown) in his individual rotary line switch RLS. Rotary lineswitch RLS now operates in the well-known manner to select an idle firstselector, such as selector FS in Figure 4. In response to dialling thefirst digit 4 selector FS operates its vertical magnet in the well-knownmanner to elevate its wipers opposite the fourth level of bank contactsand thereafter automatically rotates its wipers in search of an idleconnector switch. Assuming that the connector switch CS in Figure 4 isthe connector taken into use, selector wipers 20, 22 and Z3 stop on bankcontacts 48, M and 42 associated with this connector. Connector CS isoperated first in a vertical direction in response to the second digit 5and then in a rotary direction in response to the last digit 6 to engagethe bank contacts terminating the called subscribers line. If the calledline is idle the connector switches through and rings the calledsubscriber C in the well-known manner. When the called party answers,the desired local connection is completed and after conversation theswitches are released in the usual way.

It will now be assumed that subscriber C in desiring to complete a localcall to subscriber C dials the exchange code 7'7 and then the digits 4,5 and 6. The rotary line switch RLS and the first selector FS operate inthe same manner as just described with the exception that the firstselector is now elevated to the seventh level instead of the fourth, andis automatically rotated in search of an idle second selector. Assumingthat the second selector SS, Figure 4, is the first idle second selectorin the seventh level then the wipers 28, 2!, 22 and 23 stop inengagement with the bank contacts 30, 3|, 32 and 33 respectivelyassociated with selector SS. A circuit is now completed over the callingline loop in operating line relay 430 as follows: from ground at camsprings 415 at the upper right, lower winding of relay 430, contacts 423and 4M, conductor 53 and contacts 33, wipers 23 and [9, through thecalling loop, wipers l6 and 20, contact 30, conductor 50, contacts M2and 42L and through the upper winding of line relay 430 to battery. Atcontacts Q32 relay 430 completes a circuit for operating theslow-to-release release relay 446 from grounded contact 421, and atcontacts 43! completes a circuit for operating the start relay 536 indirector-finder DF, Figure 5, as follows: from grounded contacts 418 ofthe busy key BK, contacts 416, 43! and 412, start conductor Q in cable406, winding of relay 530, contacts 53! and 52 I, through the series ofcontacts 551, 549 and 539 on the respective start relays associated withthe different second selectors, and through the winding ofslow-to-operate guard relay 523 to battery. Release relay 440 atcontacts 442 grounds conductor 52 by way of contacts 41'! to maintainthe first selector FS and rotary line switch RLS in operated position,and to maintain ground on incoming test conductor E2 to busy the callingline. At contacts 44-5 relay 349 completes an energizing circuit throughthe 7 lower winding of slow-to-release change-over 9 relay 459 fromgrounded vertical off-normal contacts 49!.

Start relay 559 in the director finder energizes over the above tracedcircuit and closes contacts 532 first to lock itself through relay 529before opening its original energizing circuit at contacts 53! and 539.At contacts 539 relay 539 opens the circuits to the other start relays,such as relays 549 and 559, to prevent their energization at this time,at contacts 533, 535, 536 and 531 completes a circuit for one of theconnect relays, such as relay 9, dependent upon which idle director hasbeen preselected for use. In this case, since the director in Figures 6,7, 8 and 9 has been preselected for use by the energization of relay569, connect relay 5l9 is operated over the following circuit: fromground at back contacts 6963 of seize key SK, Figure 10, conductor 599included in cable 599, back contacts 59!, make contacts 563, contacts533, thru the upper winding of connect relay 5), and thru the commonresistance R to battery.

It is believed advisable at this point to explain in detail how thedirectors are preselected for use in rotation. As shown in the detailcircuits, relay 569 is energized over the following circuit: from groundat back contacts 622, conductor 592, contacts 56!, conductor 593,off-normal contacts 841, 931 and M1, conductor 631, contacts 656,conductor 594 and thru the winding of relay 569 to battery. In casedirectors corresponding to relays 561, 568 and 569 were also idle thenthese relays would normally also be operated over similar circuits intheir respective directors. Whenever a director is taken into use therelease relay corresponding to relay 629 is energized in a mannerdescribed hereinafter to disconnect ground from the correspondingconductor 592 to release the allotter relay corresponding to relay 569.When all directors are busy all of the allotter relays 569, 561, 569 and559 and the all-directorsbusy relay 519 will be deenergized. However, assoon as any one of the directors become idle, conductor 512 will begrounded to re-operate relay 519. In addition, when all of the relays569, 561, 568 and 569 are restored, relay 589 is operated from groundedconductor 599, back contacts 59!, 563, 564,- 565 and 565, and winding ofrelay 589 to battery. In case there are one or more directors idle,relay 519 will be operated and relay 569 at contacts 58! completes acircuit for Operating the slow-to-operate reset relay 599. At makecontacts 59! relay 599 connects grounded conductor 599 to the breakcontacts, such as contact 562, on all the allotter relays to energizethe allotter relays corresponding to idle directors. For example,assuming that the director in Figures 6, '1, 8 and 9 is idle, thenground is extended thru contacts 562, conductor 593, thru off-normalcontacts 941, 831, and M1, conductor 631, contacts 655, conductor 594and thru the winding of relay 569 to battery. Allotter relays 561, 569,and 569 are also operated over similar circuits providing thecorresponding directors are idle. At contacts 563 relay 569 preparescircuits to connect relays 529, 5l9' and 5l9" for connecting thisdirector to the second selector originating the next call. Contacts 564,565 and 556 are likewise operated, if the corresponding directors areidle, to prepare circuits for operating the connect relays for thesecond, third and fourth directors. The allotter relays, upon operation,lock thru contacts, such as contacts 56!, until the associated directoris taken into use. The operation of any one allotter relay opens the 10circuit of relay 589 which releases and at contacts 58! opens thecircuit to the reset relay 599 which then deenergizes to prepare thecircuit for operating the connect relays.

Returning now to the time when connect relay 5!9 was operated, saidrelay at contacts 5l2 completes a locking circuit from contact 534 thruits lower winding and at contacts 51! grounds the previously mentionedmultiple to similar relays 5!9 to prevent their energization. Atcontacts 55' and 5M relay 5i9 operates the director line relay 6 59 overconductors 523 and 524 in the cable 599, conductors 492 and 493 in cable499 and the calling loop; at contacts 5!!! completes a circuit forenergizing relay H9 in selector SS and relay 649 in the director asfollows: from ground at vertical ofi normal contacts 48!, contacts 445,434 and 4. 9, winding of relay 4!9, conductor 491 in cable 499, contacts539 and 5l9, conductor 529 in cable 599, contacts 658, and thru thewinding of relay 649 to battery; and at contacts 5!!! relay 5 I9 groundsthe BY conductor in cable 599 to mark this director as busy to the testcircuit of Figure 10.

When relay 4! 9 in selector SS operates, contacts 4|9 close a lockingcircuit independent of the vertical off-normal springs 48!, contacts 4l1open one of the shunt circuits around relay 429; contacts 4|5 groundconductor 496 to maintain the locking circuit of relay 5!9; contacts 4H5open the circuit of start relay 539 and relay 529; contacts 4!! and M3connect the selector line relay 439 to a closed loop comprisingconductors 49! and 494 in cable 499, contacts 5!5 and 5l6, conductors525 and 526 in cable 599, and pulsing contacts 959 in Figure 9 formaintaining relay 439 energized; and contacts M2 and M4 disconnect linerelay 439 from the calling loop.

In the director finder, relays 539 and 529 restore when their circuit isopened at contacts M6, and re-close the start relay chain circuit. Itshould be noted that this chain circuit is so arranged that in case ofsimultaneous calls wherein two start relays, such as relays 539 and 549,are simultaneously energized, only one of the relays, that nearest thebattery supply thru relay 529, is permitted to fully operate and lock.This arrangement prevents two selectors seizing the same director. Atcontacts 533 and 534 the circuits to the upper and lower windings ofrelay 5! 9 are interrupted, but this relay is now maintained operatedover conductor 496 from ground at contacts 418. At contacts 538 theoriginal energizing circuit for relays M9 and 649 is opened, but theserelays are maintained operated over contacts 625, conductor 528,contacts 5I8, conductor 491 and contacts M8, due to the operation ofrelease relay 629 in response to the operation of the director linerelay 6!!! to close contacts 625.

It should be noted that relay 569 is deenergized, as soon as thedirector line relay 6 9 and release relay 629 are operated, to preselectthe next idle director. Let us assume that the second director is idleand that relay 561 is in operated position when relay 569 restores andthat start relay 539 has not as yet restored. Under these conditions acircuit is completed from grounded conductor 599, back contacts 59!,back contacts 563, front contacts 564, closed contacts 535 on relay 539,thru the upper winding of a second relay, not shown, similar to relay5"] and associated with the second selector, thru the multipleconnection previously referred to and the resistor R to battery. Thiscircuit is ineffective however,

11 due to being shunted by ground from contacts l of the first connectrelay, which thus guards the held director. This momentary circuit tothe second relay is opened at contacts 535, as soon as relay 539restores.

In the director, line relay Sill energizes as previously described andat contacts 5 completes the circuit for energizing release relay 525. Atback contacts 522 relay 62b disconnects ground from conductor 592 torestore allotter relay 555, and at front contacts 522 grounds holdconductor 5I5. At contacts 525 relay 6'25 maintains relay 640 inoperated position over conductor 528 as previously described. Relay Bupon first operating over conductor 529 at contacts 64E closes a circuitto the busy lamp BL, at back contacts 642 removes one of the groundsfrom the common all-director-busy lead 512, at contacts 543 prepares acircuit for time pulse relay 565 from time pulse lead 628, at contacts54% opens a point in the circuit to interrupter relay 953, and atcontacts 545 prepares a circuit for shunting the impulse contacts 959 ofpulsing relay 955. The director is now ready to receive the second digitof the called number.

One of the features of the invention relates to the provision in thesecond selector SS for automatically rotating to an 11th position tooperate the cam springs and give the calling subscriber a busy tone incase the calling subscriber dials the second digit before an idledirector is connected up for use. Assume now that the calling subscriberdials the second digit before an idle director is seized and in thiscase relay 4H} has not been operated. In response to the second digitline relay 435 is operated in accordance with the digit dialled to stepthe wipers opposite the level corresponding to the digit dialled. Eachpulse of the digit drops relay 430, to close a circuit for the verticalmagnet as follows: grounded contacts 427, back contacts 433 of linerelay 435, contacts 443 and thru the winding of the vertical magnet 480to battery. A multiple circuit extends thru the upper winding of relay450 to maintain this changeover relay in operated position duringdialling. Release relay 440 is also maintained in operated positionduring dialling due to its slow release characteristics. On the firstvertical step of the wipers, vertical off-normal springs 48!, 432 and483 operate. Springs 48! open the original energizing circuit of relay450 but this relay is now maintained operated over its upper winding.Springs 48| also open the operate circuit of relay 4l0 to prevent theoperation of this relay after the selector shaft has taken one step,while springs 483 close to prepare a circuit for release magnet 495, andsprings 482 complete a circuit for relay 460 from ground at contacts442, by way of contacts 451. At contacts 452 relay 36i? completes alocking circuit for itself including contacts 42?, 4B2, 41! and 482.Shortly after the last pulse of the second digit, changeover relay 450restores and at contacts 452 closes a circuit including contacts 42,452, 445 and 45! for operating the rotary magnet 4T5. Near the end ofthe first rotary step of the wipers rotary magnet 41!] operatesinterrupter contacts 47: to open the locking circuit of relay 455 whichdeenergizes and at contacts 45l opens the circuit to the magnet 4T0.Magnet G15 releases and closes contacts 4 H A circuit may now be tracedfor re-energizing relay 455 as follows: from ground at contacts 442,contacts :ill of relay 4!!! which did not operate because there was noCfl i2 seizure of an idle director, contacts 425, 41! and 432 to relay460 and battery. Relay 460 at contacts 46! again closes the circuit tothe rotary magnet 410 which again steps the wipers and again interruptsthe stepping relay 455. The rotary magnet 415 and relay 455} interact asdescribed until the wipers take their eleventh rotary step at which timecam springs CS and CS are operated. On the first rotary step of theshaft and wipers also, rotary off-normal contacts 4'52 open the startcircuit to the director finder start relay 530 which releases thedirector finder to further guard against the seizure of an idle directorand the operation of relay 4m in the second selector. At the 11th stepcam contacts M4 complete a circuit for again operating relay 456, fromground at contacts 442, by way of cam springs 414, contacts 445 andlower winding of relay 450 to battery. At contacts relay 45!) opens thecircuit to the rotary magnet 415 to prevent its re-operation. Theoperation of cam springs 475 connects busy tone and ground fromconductor 41'! through the lower winding of line relay 430 in place ofdirect ground at contacts 415 to transmit a busy tone to the callingsubscriber over the talking conductors.

When the calling subscriber hears the busy tone, such subscriber willreplace his receiver to release line relay 430 which causes the releaseof the second selector, the first selector FS and rotary lineswitch RLS.At contacts 432 relay 430 opens the circuit of release relay 440 whichdeenergizes after an interval. At contacts 442 relay 445 removes groundfrom control conductor 52 to release the first selector FS andlineswitch in the well-known manner and also opens the circuit to relay450 which deenergizes. At contacts 453 relay 45B completes the circuitfor operating release magnet 490 as follows: from ground by way ofcontacts 421, 433, 4414, 453 and 483 to release magnet 490 and battery.Release magnet 490 operates and releases the shaft and wipers in thewell-known manner. When the shaft reaches normal position the Verticalofi-normal springs are restored and at contacts 483 open the circuit ofrelease magnet 495. The second selector SS is now fully restored and mayagain be used in establishing a connection.

With normal operation however, an idle director will be seized beforethe calling subscriber has had time to dial the second digit, and willbe waiting for this digit, which in the present case will be a '7, aspreviously stated. In response to the receipt of the second digit '7,via conductors 402 and 483 through cable 400 and conductors 523 and 524thru cable 569, line relay 6H1 drops back seven times to step the wipers8H! and 8 of switch U into engagement with their seventh bank contactsby operating the stepping magnet 815 from grOund at back contacts 6! I,through contacts 62L back contacts 574, 684, 694 and E04 and the windingof magnet 8|5 to battery. A branch of this circuit extends from backcontacts 674 thru the lower winding of relay 630 to cause this relay tooperate. Relay 530 remains operated during the succeeding pulses, due toits slow release characteristics. On the first rotary step of switch U,01T-no1mal springs 8|! open and 8E8 close. Springs 8| 1 open anotherpoint in the circuit of allotter relay 560 to prevent its energizationand springs 8H3 prepare a circuit for relay 650.

Relay 630, upon operating, at make contacts 53l completes a circuit foroperating stepping magnet 825 of sequence control switch SC by way 13 ofback contacts 60! and conductor 6l8. Magnet 825 steps .wipers 829 and82! into engagement with their first set of bank contacts and atcontacts 829 completes a circuit over conductor M6 for simultaneouslyenergizing both the upper and lower windings of relay 699. Relay 669 isa differential relay which does not energize at this time due to itsopposing windings and is operated in its initial step to close contacts693 by an inductive kick only when ground is removed from conductor 6!6.Shortly after the termination of the second digit 7 relay 639 restoresand at make contact 63! opens the circuit to magnet 825 whichdeenergizes and removes ground from conductor 6!6. When ground isremoved from conductor 6l6 an inductive kick is generated in relay 699sufiicient to close contacts 693. The closure of contacts 693 nowcompletes a circuit from grounded hold conductor 6 thru the lower andupper windings of relay 609 in series to battery. As will be noted, thecurrent flow is now in such a direction that both windings are aidinginstead of in opposition and relay 696 operates completely. At contacts696 relay 699 completes a circuit for operating relays 19!] and 129 inseries, at front contacts 69! and 692 prepares the circuit for thesecond kick-up transfer relay 699, at contacts 694 transfer the pulsingcircuit from conductor 632 to 634 to cause the operation of the hundredsstorage switch H is response to the next digit, and at contacts 695completes a circuit for operating relay 9!!! from grounded holdconductor 6!5 by way of conductor 661, the first bank contacts and wiper82! of the sequence switch SC, and the lower winding of relay 9l9 tobattery. At contacts 661 relay 699 transfers the time pulse conductor629 from the restrict relay 116 and the transfer relay 639, to the upperwinding of cut-01f relay 659.

The circuit energizing relays 199 and 129 in series may be traced asfollows: from ground at back contacts 63!, contacts 606 and 696,conductor 6!2, left-hand winding of relay 199, conductor 896, multipledcontacts 9!2, wiper BM? in engagement with the seventh bank contact,conductor 802 and thru the left hand winding of relay 129 to battery. Atcontacts 106 relay 199 looks to the grounded hold conductor 6 I 5 andalso completes a circuit for operating relay 169. At make contacts 1192relay 199 connects make contact 12! to a dead terminal therebypreventing the operation of relay 119. Relays 129 and 169 at contacts123 and 163 complete a circuit for operating the digit skip relay 949 asfollows: from grounded conductor 664, back contacts 93!, conductor 850,wiper 829 in engagement with its lst set of bank contacts, conductor65!, back contacts 113, front contacts 163, contacts 123, the multipleconnections cross-connected to conductor P included in cable 809 andthru the upper winding of relay 949 to battery.

Relay 9!9 operates, over its previously traced circuit, and at contacts9!3 completes the circuit for energizing interrupter relay 953 asfollows: from grounded conductor 6I5, back contact 931, contacts 928,back contacts 926, contacts 9!.3, back contacts 936, conductor 639,contacts 623, conductor 638, contacts 95! and thru the winding of relay953 to battery. Digit skip relay 949 upon operating over its previouslytraced circuit at contacts 942 prepares a locking circuit for itself, atcontacts 943 closes a shunt around pulsing contacts 959 and at contacts94! grounds stop conductor L!. Relay 953 at contacts 954 closes alocking circuit for itself thru counting relay 9Y2 as follows: fromgrounded conductor 5H5, back contacts 931, contacts 928, 951, 999, 992,995, 919, and 91! and thru the winding of counting relay 912 to battery.Interrupter relay 959 at contacts 95! opens the circuit of interrupterrelay 953 which releases and at contacts 952 opens the circuit to relay955, which also deenergizes and at contacts 956 opens the circuit tointerrupter relay 959. Relay 959 restores and recloses the circuit torelay 953 at contacts 95! to restart the interrupter relays 953, 955 and959 in a new cycle as just described. The cycle of operation of theinterrupter relays continues until ground is removed from conductor 639by the operation of stop relay 929.

In order to describe the complete operation of the counting relays intransmitting the outgoing digit 0 for example, it will be assumed thatthe digit skip relay 9 59 is not operated and therefore stop conductorLi is not grounded and outgoing pulsing contacts 959 are not shortcircuited by contacts 943 of relay 949.

Counting relay 912, upon energizing, at con-,

tacts 96? connects conductor L! to relays 929 and 939, and assumingconductor L! is not grounded at this time neither stop relay 929 or 939operate. At contacts 969 relay 912 prepares a circuit for the secondcounting relay 916, and at contacts 919 completes a new circuit forrelay 912, independent of the chain of back contacts on the othercounting relays, by way of back contact 96! and contact 951. At contacts913 relay 912 prepares a locking circuit for itself in series with relay969 which at this time is shunted by ground on both sides of its lowerwinding. When interrupter relay 959 restores however the short circuitaround relay 969 is opened and relay 969 energizes in series with relay912 as follows: from grounded conductor 6i5, back contacts 931, contacts929, lower winding of relay 969, contacts 989 and 913, and through relay912 to battery. At back contacts 96! relay 959 opens the countingcircuit to the Odd conductor and at make contacts 96! connects thecounting circuit to the Even conductor to prepare a circuit to thesecond counting relay 916.

When interrupter relay 955 is operated on the second cycle operation, itextends ground over contacts 959 and front contacts 962 through theupper winding of relay 969 to hold relay 969 energized, and at contacts951 causes the same ground to operate the second counting relay 916 overmake contacts 96!, the Even conductor and contacts 969. At contacts 914relay 916 connects conductor L2 to the stop relays 929 and 939 but againwithout result, since conductor L2 is not marked with ground on thiscall. At contacts 911 relay 916 completes a locking circuit for itselfby way of contacts 999, 928 and 931 to grounded conductor 6!5, atcontacts 918 opens the chain circuit for the first counting relay 912,at contacts 919 prepares a circuit for the third counting relay 996, andat contacts 989 opens the locking circuit of the first counting relay912 which deenergizes.

When interrupter relay 955 restores, said relay at contacts 959 opensthe locking circuit of relay 969 which deenergizes to transfer thecounting 15 circuit back to the Odd conductor to further prepare thecircuit to the third counting relay 986.

When interrupter relay 955 is operated in the third cycle of operationcounting relay 9'99, is operated from grounded conductor 915, contacts931, 928, and 951, back contacts 961 and contacts 919 thru the windingof relay 996 to battery. At contacts 958 relay 955 closes a shortcircuit around the lower winding of relay 999. Relay 986 at contacts 981closes another short circuit around the winding of relay 960 as well aspreparing a locking circuit for itself in series with relay 969. Atcontacts 981 relay 986 connects conductor L3 to stop relays 920 and 939without effect, and at contacts 993 prepares the circuit for the fourth.counting relay 991. At contacts 984 relay 989 opens the locking circuitof relay 916 which restores.

Wheninterrupter relay 955 again deenergizes, the short circuits around,the lower windings of relay 960 are opened, and this relay now energizesin series with relay 986 from grounded conductor 615 by way of contacts931, 923, lower winding of relay 969, contacts 994 and 981 and windingof relay 986 to battery. Relay 959 again transfers the interruptercounting circuit from the odd to the even conductor.

When interrupter relay 955 operates in the fourth cycle, counting relay991 is operated from grounded contacts 951, make contacts 951, contacts983 and thru relay 991 to battery. At contacts 988 relay 991 connectsconductor L4 to the stop relays 926 and 930, and at contacts 999completes its own locking circuit by way of contacts 991, 928 and 931.At contacts 999 relay 991 prepares the circuit of the fifth countingrelay 901, and at 994 opens the locking circuit of the third countingrelay 986 which restores. Relay 989, however, is maintained operatedover its upper winding and contacts 962 and 959 until relay 955restores. When relay 955 restores relay 969 also restores and transfersthe interrupter counting circuit to the odd conductor.

When interrupter relay 955 operates in the fifth cycle, counting relay9.61 operates from grounded contacts 951, and back contacts 95% andcontacts 993. At contacts 995 relay 96% connects conductor L5 to stoprelays 926 and 999, and at contacts 991 opens the circuit of relay 991which restores. At contacts 999 relay 991 locks independent of contacts993, and at contacts 902 operates relay 966 over contacts 929 and 931 togrounded conductor 615. Relay 969 at contacts 995 prepares its ownlocking circuit in series with relay 969 but relay 999 does not operateat this time because of the short circuit by way of contacts 995 and902. When interrupter relay 955 restores, the circuit to relay 991 isopened and relay 961 restores and at contacts 992 removes the shortcircuit from relay 993 to permit this relay to operate in series withrelay 966 from grounded conductor 615, by way of contacts 931, 928 and965. Relay 963 at contacts 994 disconnects the marking leads L1, L2, L3,L9 and L5 and switches over to prepare circuits to leads L6, L1, L8 andL9.

The interrupter relay 955 is operated for the sixth to tenth pulses andrelays 912, 916, 999, 991 and 991 are operated in the order named forthe sixth, seventh, eighth, ninth and tenth pulses in the same manner asdescribed for the first to the fifth pulses. However in this case, sincecontacts 964 are operated, the stop relays 920 and 930' are sequentiallyconnected to the marking, or stop, conductors L9,, L1,, L8 and L9 and toground at contacts 996, for the tenth pulse. Whenever any one of thestop conductors is grounded thru wiper 826 and operated contacts cf therelays in Figure '1. the stop relay 929 is operated to stop outgoingpulse transmission for that particular dig-it, or if no stop conductorsare grounded the counting relay chain counts ten pulses and contacts 996close to operate the stop relay. Outgoing impulses are generated atcontacts 959 of interrupter relay 9,55 and transmitted over the outgoingconductors 525 and 526, contacts 515 andv 516' in Figure 5, conductors991 and 599 to second selector SS in Figure 4.

When counting relay 991 is operated by the tenth interrupter pulse,ground at contact 999; completes a circuit for operating stop relay 929as follows: ground, contacts 996, 964 and 923 and thru the upper windingof stop relay 929 to battery. A branch of this circuit also extends thruboth the upper and lower windings of stop relay 999 but since this relayis a differential relay, it does not operate at this time.

Stop relay 929' at contacts 921 completes a circuit for energizingstepping magnet 8.25 of the sequence control switch SC by way ofcontacts 912, 932 and 921 and the magnet steps wipers 929 and. 821 intoengagement with their second set of bank contacts. At contacts 922 relay929 closes its own locking circuit from grounded conductor 694 as wellas maintaining a circuit thru the upper winding of relay 939; atcontacts 924 and 935 interrupter relay 959 is maintained energized fromgrounded contacts 999; at back contacts 926 the circuit to interrupterrelay 953 is maintained open; and at contacts 929 the locking circuit toany operated counting relay is opened to cause such relay, or relays, torestore. Due to the fact that none of the stop conductors L1 to L9,inclusive, were grounded, the interrupter relay 955 at contacts 959 hassent out ten pulses over conductors 525 and 526 to the switch train.

Having described the circuit operations of s the counting relays when anoutgoing digit "0 is to be transmitted for the purpose of giving a fulldetail description of the counting relay circuits, we will now return tothe local call and since digit skip relay 949 is operated in a localcall, contacts 951 are closed to ground stop conductor L1, and thereforestop relay 920 is operated from said grounded contact 941 and contacts961, 969 and 923-, when the first counting relay 912 is first operated.In this case, since the digit skip relay 940 is operated, contacts 993short circuit outgoing pulse contacts 959 so that the pulses generatedby contacts 959 are ineffective. Stop relay 920 upon operating, operatesmagnet 325, locks itself, maintains relay 959 operated, maintains thecircuit to relay 953 open, and opens the locking circuit for theoperated counting relays, in this case relays 912 and 969, in the samemanner as previously described.

When the counting relays restore, ground is removed from the lowerwinding of stop relay 939 by disconnecting the grounded stop conductor,such as L1, from such lower winding. When the circuit thru the lowerwinding of relay 939 is opened, relay 939 is operated over its upperwinding from grounded conductor 66% and contacts 922'. Relay 956 alsorestores when the release of the counting relays disconnects ground fromthe lower winding of relay 939, and at contacts 951 prepares a circuitfor interrupter relay 953. .Relay .939,-upon operating, at make contacts93! looks digitskip relay 949 from grounded conductor .654 and makecontacts .93! and 992 thru its lower winding, and at back contacts 93!disconnects ground from conductor .859 and wiper 829. At contacts 932relay 939 releases magnet 925; at contacts 933 grounds stop conductorL1, but without effect at this time; at make contacts 939 prepares acircuit for .,the lower winding of relay 929; at contacts 935 and .931r.e.-operates relay 953 from grounded conductor l5, by way of contacts931, 921, 926 and 939, conductor 639, contacts 523, conductor 638, andcontacts 95!; and at contacts 938 closes another shunt around outward.pulsing contacts 959. This latter shunt circuit may be .traced.fromcontacts 959, contacts 938, conductor 611, contacts 995, andconductor 525, back to contacts 959.

Interrupter relay 953 reoperates relay 955 and the latter relayreoperates relay .959 and the first counting relay 912 .fromgroundedconductor 5!.5, make contacts 931, 921 and 951, contacts 999,392, 985,918.and .91.! and through the winding ofrelay 9.12 .to battery. Relay912 locks, as previously described and at contacts 99'! connectsgrounded stop conductor .L!, which is still grounded .from contacts .94!of digit skip relay .949, to thelower winding of operated stoprelay.9,29 by way of contacts 994 and 939. Relay 929 is.a.difierentialrelay, and with both windings energized in opposition relay 929restores.

At contacts 923 ground is maintained thru the upper winding .of relay939 to hold this relay operated, and at contacts.925 relay 959 ismaintained operated from grounded stop conductor .Ll. .At make contactsv926 and 921 relay .929 opens the circuit of relay 953, and at makecontacts 921 opens the circuit .of relays 912 and 969. .Relay -912 atcontacts 951 disconnects grounded. stop conductor L! from both windingsof relay 929..and from .the upper winding of relay 939 whereupon thelatter relayrestores. Relay 959 also restores and both stop relays Y929and 939 are.again in their normal positions. .At make contacts 93! thelocking circuit to relay 949 is opened, but at back contacts .93! thecircuit to the upper winding is closed from grounded conductor 664,conductor .959, wiper829 in second position, conductor .852, backcontacts 115, front contacts 165,

contacts 125 and thence ov r the multipled conductor P to the upperwinding of digit skip relay 94.9 to battery to .re-energize this relay.At contacts 9.33 relay 939 removes ground from ccnductor.L1; atcontacts934 opens a point in the circuit to the lower winding of relayr929 andprepares a circuit to the lower winding of relay 939, and .at backcontacts ,936 and 931 completes the previously traced circuit throughcontacts 9l3 for re-operating interrupter relay 953.

In-the same manneras just described interrupter relay 953 operatesrelays 9.55 and 959 and relay 955 reoperates the first counting .relay912 which at contacts .951 again connects grounded stop conductor L! tostop relay 929 which operates and causes the sequence switch 1nagnet-925to step its wipers into engagement with their -third set of bankcontacts. Stop relay 929 also momentarily stops the interrupter relaysand releases the operated counting relay. When the counting relayrestores relay 939 is operatedand relay 959 restores. Relay 953reoperates relay 955 and the first counting relay 912 to connectgrounded stop conductor Li to both windings of relay 929 to cause itsrelease which in turn again restores the counting relay 912 todisconnect stop conductor Ll, to cause relay 939 to restore. Relay 959restores and reoperates relay 953 to start another cycle of operations.

The interrupter relays 953, 955 and 959, the counting relay 912, thestop relays 929 and 939, the digit skip relay 949, and the steppingmagnet 825 continue to operate in the manner just described until thewipers829 and 92! of the sequence contro1 switch SC are operated intoengagement with their sixth set of bank contacts at which point thecircuit to relay M9 is openedat wiper 82! provided the callingsubscriber has not yet dialled the third, or the hundreds, digit of thecalled number. In this case relay 919 restores and at contacts 9i3 opensthe circuit to thefirst interrupter relay .953 to prevent re-cycling ofthe interrupter .relays. It will be noted that the digit skip relay 999was operatedover wiper 329 when in engagement with its first five setsof bank contacts over conductors 85!, B52, 853, 854 and -855, operatedcontacts of relays 169 and 129 and over the multipled jumper conductorconnected to conductor P. The operation of digit skip relay..949at.contacts 94! has-grounded stop conductor L! to speed uptheoperationof the stop relays and the operation of thesequence controlswitch SC from its first to its sixth set of bank contacts, and atcontacts 943 has shunted the pulsing contacts 959 with the resultthatall outgoin oifice routing digits have been skipped with theresultthat the director is now ready to retransmit thelast three digits of thecalled number, generally called the subscribers number.

When the calling subscriber dials the third digit 4, which is the seconddigit dialled into the director and the hundreds digit of the called rnumber, the line re1ay.6l9 is restored four times to transmit fourpulses to stepping magnet 845 of the hundreds register switch and tostep-the wiperMB thereof into engagement withits fourth bankcontact tostore the hundreds digit of the called number. The circuit for operatingmagnet 845 extends from ground at back contacts 5! I,

contacts 62!, 919, 684, 994 and 994, conductor 934 and thru thewindingofmagnet-Btl to battery. A branch of this circuit extends fromcontacts 614 thru the lower winding of relay 539 which operates and ismaintained operated during .the pulsing period. At contacts .53! relay639 closesa circuit for energizing both windings of kick-up transferrelay 999 as follows: ground at make contacts 93!, make contacts 69!,break contacts 99!,.thruthe upper winding of relay-699 to battery, andthru the lower winding of relay 699, back contacts 692, .front contacts692, and thru the associated resistance K to battery. Relay 599 is .adifierential relay and since the currents flowing thru the 'two windingsare now in opposition the relay will not operate. Relay 639 releasesshortly after the pulsing period and at contacts 53! opens the abovetraced circuit whereupon an inductive kick is developed in relay 599sufiicient toclose contacts 593. When contacts 593 connect groundedconductor'fil5 to the lower winding of relay 599, the original circuitbeing open, both windings are energized in H Series, andthe relay thenoperates fully. At contacts 696 relay 698 opens the original energizingcircuit of relays 188 and 128 but these relays are maintained operatedover their locking circuit. At contacts 69! relay 699 prepares a circuitfor the next transfer kick-up relay 688 as well as preparing a circuitfor release magnet 8!6 of switch U. At make contacts 694 relay 698prepares a circuit to stepping magnet 835 of the tens register switch T,and at contacts 695 completes a circuit for re-energizing relay 9!8 asfollows: grounded conductor 6l5, contacts 695, conductor 668, sixth bankcontact and wiper 82! and multipled contacts, and thru the lower windingof relay 9!!) to battery. At contacts 9l3 relay 9!8 completes thepreviously traced circuit for energizing the first interrupter relay 953to operate the interrupter relays, counting relays and stop relays, totransmit an outgoing digit corresponding to the digit just registered inthe switch H.

In response to dialling the fourth, or tens digit line relay 6!8deenergizes five times and operates stepping magnet 635 to step wiper838 of the tens switch T into engagement withits fifth bank contact overthe following circuit: ground at back contacts 6! contacts 62!, 614,

684 and 694, conductor 633 and thru the windv8H5 extends from ground,make contacts 63!, 68!

and 69!, contacts 953 and 686, conductor 6!!) to release magnet 8 i 6and battery. A branch of this circuit extends from make contacts 69! andback contacts 68! through the upper winding of relay 688 to battery andthru the lower winding of relay 688, back contacts 682, makecontacts 692and 682 and thru the associated resistance K to battery. Release magnet8! 6 operates to restore the wipers 8!8 and 8! of the units register tonormal to prepare it to receive the incoming units digit. Shortly afterthe dialling of the tens digit, relay 638 restores to open the circuitto release magnet 8 I 6 and to open the circuit thru the two windings ofdifferential transfer relay 688. When the 'circuit thru the two windingsof relay 689 is opened, an inductive kick is generated to cause relay699 to close contacts 683 whereupon ground from conductor 6!5 extendsthru the lower and upper windings to cause the relay to fully operate.Relay 688, at make contacts 69! and 682 prepares the circuit to the nexttransfer relay, at contacts 686 opens the circuit to release magnet 8!6, at make contacts 684 prepares the pulsing circuit to the steppingmagnet 8! 5 of switch U, and at contacts 685 connects grounded conductor6!5 over conductor 669 to the seventh bank contact of switch SC.

In response to dialling the fifth, or units digit -6, line relay 6!!!deenergizes six times and 68!, 69!, 68!, and 61! thru both windings ofrelay 618, contacts 612, 682, 692, and 682', and the associatedresistance to battery. Differential transfer kick-up relay 618, in amarmer sim lar to the other transfer relays, operates to close itscontacts 613 when relay 638 restores, at which time both windings aideach other and the transfer relay fully operates. At contacts 614 relay619 opens the pulsing circuit and at contacts 615 connects groundedconductor 6!5 to the eighth bank contact of switch SC to mark thereceipt of the units digit.

It will be remembered that following the registration of the hundredsdigit "4 in switch H, the wiper 82! of the sequence control switch SC isstepped into engagement with its sixth bank contact to complete thecircuit for operating relay 9!8, and at contacts 9!3 this relayinitiates the operation of interrupter relays 953, 955 and 958 aspreviously described. With switch wiper 828 in the sixth position, acircuit is no longer completed for digit skip relay 948, with the resultthat the outgoing pulsing contacts 959 are no longer shorted by contacts943, and the director is ready to transmit the outgoing digitcorresponding to the registered digit in the hundreds register H. Sincethe digit 4 is registered in the register H, the first four countingrelays 912, 916, 986 and 99! are operated by interrupter relay 955 aspre- 'viously described, and the pulsing contacts 959 have opened fourtimes to transmit four outgoing pulses over conductors 525 and 526,contacts 5!5 and 5!6, conductors 48! and 484 in cable 488, contacts 4!!and M3, contacts 42! and 423, both windings of line relay 438 tobattery, and to ground thru contacts 415.

In response to the operation of the fourth counting relay 99!, stoprelay 928 is operated from the hundreds register switch H as follows:from grounded conductor 664, back contacts 93!, conductor 858, wiper 828in engagement with its sixth bank contact, wiper 848 of the hundredsregister switch H in engagement with its fourth bank contact, conductorL4 in cable 988, contacts 988 of the fourth counting relay 99!, backcontacts 964, contacts 923, thru the upper winding of stop relay 928 andthru both windings of relay 939 to battery. Relay 928 operates over thiscircuit and at contacts 924 holds relay 958 operated to stop theinterrupter relays momentarily, and thus stop the outgoing pulsetransmission. Relay 928 also at contacts 92! completes the circuit foroperating stepping magnet 825 to step wipers 828 and. 82! intoengagement with their seventh bank contacts in readiness to transmit thetens digit 5 stored on the tens register switch T. At wiper 82! sequencecontrol switch SC completes a new circuit for relay 9l8 over conductor669 and contacts 685. ,Relay 928 further, at contacts 928 opens thelocking circuit to the operated counting relays, in this case relay 99!,to cause its release. At contacts 988 relay 99! disconnects groundedconductor L4 from the lower winding of relay 938 whereupon said relay isoperated thru its upper winding alone. Relay 958 now releases and atcontacts 95! re-establishes the circuit for operating interrupter relay953 over contacts 931, 921, 926, 936, 623 and 95!. Relay 938 also opensthe circuit to magnet 825 at contacts 932, and at contacts 933 groundsconductor L1 to cause the counting relays to count seven pulses for theinter-digital interval between outgoing digits. At contacts 938 relay938 also closes a shunt around the pulsing contacts 959 by way I ofcontacts 945, to prevent transmission of out- "be operated.

21 cause the counting relays to count up to :seven, at which time relay915 will be operated "for the second time and relays 963 'and'969 willAt contacts :915 relay I916 completes a circuit from ground, contacts9l2, 933, 915, 999 and 939 thru the lower winding of relay 929 tobattery. Since stop relay 929 now has its upper winding energized overcontacts 922 and is differential, the circuit thru the lower windingcauses deenergization of relay 929. -At contacts 923 and 935 the"circuit thru both windings of relay 929 is maintained until thecounting relay deenergizes. At contacts '925 interrupter relay 959 alsois maintained operated until the counting relay restores, while contacts923 maintain relay 939 operated. At contacts 921 the locking circuit tothe operated counting relays is opened and such relays 'release.Counting relay 919 at contacts 915 adisconnects ground from relays 939and 959 which restore preparatory to transmitting the outgoing tensdigit. Relays'959 and 939 again complete the circuit for reoperatinginterrupter relay 993, and relay 939 at contacts 938 removes the shuntfrom around the pulsing contacts 959.

The interrupter relays 953, 955 and 959 and the counting relays operatein the same manner as previously described to transmit the stored tensdigit. Since the digit is stored on the tens register switch T thenconductor L5 is grounded as follows: from grounded conductor 669,contacts 93!, conductor 8'59, wiper 929 in engagement with its seventhbank contact, wiper 939 in engagement withits fifth bank contact toconductor L5. When the fifth counting relay 99! operates a circuit is.completed for stop relay 929 from grounded conductor L5, contacts 995,954 and 923 and .thru the upper winding of stop relay 92.9 to battery.The interrupter relay 955 has operated five times and at contacts 959has transmitted five outgoing pulses over conductors 525 'and'526. .Atcontacts 924 relay 929 operates magnet 825 to step the wipers 929 and'92! of the sequence control switch SC into engagement with their eighthhank contacts for transmitting the units registration. At contacts 922relay 929 looks and maintains the circuit closed "thru 'both windin s ofrelay 999, at contacts 929 maintains relay 959 energized for aninterval, at contacts 929 opens the circuit to relay 953, and atcontacts 929 opens the locking circuit of the operated counting relay995 which restores. "When relay 99! restores, this relay at contacts 995removes ground from relay 959 and from the lower winding of relay 939whereupon'the latter relay operates over its upper winding, whilerelay959 restores. At contacts 939 relay 939 again shunts pulsing contacts959 for the inter-digital interval, at contacts 931 removes markingground from wiper 529, at contacts 932 opens the circuit to rcagnet 925,at contacts'933 again grounds conductor L1, at contacts 939 and 931completes the circuit for re-operating interrupter relay 959. Relay 9E9is now held operated from wiper 92! and its eighth bank contacts fromground on conductor 9l5 passing through contacts 515 and conductor 516.

The interrupter relays 955, 9.55 and .959 now resume their pulsing cycleas previously .described. Pulsing contacts 959 are now again withouteffect due to being shunted atcontacts 999, but the counting relayscount up to seven asbefore, at which time relays:919, .963,.and9B6 willagain be operated, Upon the operation-of relay 9.19, contacts 915 againcompletea circuit from ground .at contacts 9l2 through contacts 933,915, 999, and 939 and the lower winding of stop relay 929 to battery.Both windings of relay 929 are now energized in opposition and thisrelay restores. 'At contacts 921 relay 929 opens the circuit to thecounting relays and relay 919 restores and releases relays 939 and 959preparatory to transmitting the outgoing units-digit. Relays 999 and 959againcomplete the circuit of interrupter relay 953, and relay 2939 atcontacts 998 removes the shunt from pulsing contacts 959.

The'interrupter relays 953, 955, and 959 and the counting relaysoperatein the mannerpre- 'viouslydescrihed to transmit the units digit 6 storedin the units register switch U. When the-counting relay 912 is operatedfor the second time stop relay 929 is operated over the followingcircuit: from grounded conductor 694, contacts 93d, conductor 959, wiper929 :in engagement with its eighth bank contact, wiper :91! inengagement with its sixth bank contact, conductor L5 in cable 999,contacts 998,954 and 923 thru the upper winding of relay 929 to battery.In the same manner as previously described relay 92-9 at contacts 92!operates stepping magnet 925 of the sequencecontrol switch S0, atcontacts 929 holds relay 959operated, at

contacts 925 opens the circuit to relay 953, and

at contacts 928 opens the locking circuit to the counting relays tocause such relays to restore. Relay 912 at contacts "999 opens thecircuit to relay 959 and to the lower winding-oi relay 939 whereuponrelay 999 operates over its upper winding. Relay 939 at contacts 932opens the circuit to magnet 925, at contacts 995 opens the circuit torelay 959, at contacts 935 'and 991 reoperates relay 953, and atcontacts 938 shunts the pulsing contacts 959. The interrupter relays arestarted in a recycling opera- *tion-for the inter-digital interval aspreviously described. Meanwhile, interrupter relay 955 at contacts 959has transmitted the outgoing units digit 6 over the conductors 525 and526 to the switch train.

Returning now to the transmission of the outgoing hundreds digit 4 fromthe director, line relay 459 is deenergized four times to operate thevertical magnet 999 of selector SS from ground by way of contacts921,993 and 44 3 to .the vertical magnet 999 and to theupper winding ofrelay 959 in multiple. The vertical magnet-489 operates the shaft andwipers opposite the fourth level-and relay 959 at contacts 451 closesashunt around relay 929 as follows: from contacts 45!, 91!, winding ofrelay 429, cam contacts 413 and back to contacts 45L Relay 459 also atcontacts 95! connects ground from contactsAM thru vertical off-normalcontacts bank contact in the fourth level and at rotary off-normalcontacts 912 opensanother point in .the start circuit to the director.At contacts

